Food Processing: Safe, Gentle Conveyance of Delicate Materials

Food Processing: Safe, Gentle Conveyance of Delicate Materials
In every step of food processing, from receipt of raw materials through packaging, keeping foreign matter from entering the process stream, maintaining hygiene, and keeping the system free from unwanted allergens are critical objectives.

As such, many food processors are reconsidering the use of “open” conveying systems such as bucket elevators and flat-belt conveyors in favor of enclosed systems designed to prevent exposure to ambient conditions and possible contamination.

Since the 2011 enactment of the FDA’s Food Safety Modernization Act, the importance of preventing product contamination has only increased with stringent product track and trace mandates as well as consumer demands for safety.

Additionally, as food processors seek to increase production uptime and reduce laborious maintenance, the ease of cleaning such equipment is also a major concern.

“With increased regulation, the primary focus of food processors has been on preventing contamination and reducing cleaning requirements,” says Mike Judy, an independent food industry sales representative, and installer of conveying systems.

In food production, line changeovers have become a focal issue, relative to both cleanliness and changeover speed as companies are increasingly running different product lines within a single shift or day.  Despite these changeovers, processing plants are expected to maintain rigorous levels of sanitary, allergen-free operation.

“With smaller margins, food companies are producing a broader range of products, which results in more product changeovers and more attention on efficient cleaning of production equipment,” says Judy.

Also important to food processors’ bottom line is the capability of conveying equipment to reduce any potential product damage, in order to optimize quality and profit.

So, to ensure the safe, clean conveyance of even delicate materials with minimal product degradation, a growing number of food processors are turning to enclosed systems such as tubular drag conveyors that help prevent contamination and significantly ease, or even automate, cleaning.

The Disadvantages of Open Conveyor Systems

Traditionally, bucket elevators and flat-belt conveyors have been the predominant systems used to transport food products.  However, open systems like these have substantial drawbacks in terms of the potential for contamination and ease of cleaning.

Bucket elevators utilize a continuous line of buckets, either attached to each other on a rubber belt or attached by pins to two endless chains running over tracks and driven by sprockets. Centrifugal force moves the food being conveyed out of the buckets into a discharge spout as the buckets pass. This type of conveyor handles food products gently but potentially exposes it to contamination from the surrounding environment.  

Flat-belt conveyors have the same issue, and so some are covered. Unfortunately, the covers can collect residue and must be removed and cleaned between runs, a tedious and time-consuming task. 

Open conveyors also allow the product (if hygroscopic) to absorb moisture.  Given that many food processing facilities are not climate controlled, this is a very real possibility. Such moisture absorption can cause the product to expand, or clump, which can not only degrade quality but also make conveyor cleanup more difficult.  

The Advantages of Closed Conveyor Systems 

Unlike open systems, closed conveyor systems effectively seal off product from the outside environment, and any potential contamination from that source.

Although there are several types of closed systems, one popular example when conveying high-value foods that are prone to breaking or crumbling is tubular drag cable conveyors. These systems gently move product through a sealed tube using a coated, flexible stainless-steel drag cable pulled through on a loop.  Solid circular discs (flights) are attached to the cable, which pushes the product through the tube without the use of air. The coated cable ensures that no debris accumulates within the strands of the cable, as the cable is totally sealed.

The enclosed nature of tubular drag systems ensures no dust escapes: that could lead to an unsanitary and potentially dangerous coating of dust on the floor or process equipment. The result is a safer, cleaner, dust-free work environment and reduced risk of dust explosions if the product is in powdered form.

“Closed-system tubular cable conveyors like Cablevey Conveyors have become popular because once the product is in the tube, it cannot be contaminated.  That is critical for a lot of food products today,” says Judy.

Cablevey Conveyors is an Oskaloosa, Iowa based premium, specialty material moving, mechanical conveyor company that has designed, engineered, and serviced enclosed cable and disc tube conveyors for almost 50 years, and is in more than 66 countries.  

In the food industry, the conveyors are utilized for products such as nuts, cereal, snacks, beans, seeds, and coffee.  The systems can convey up to 2000 cubic feet per hour of chunks, flakes, pellets, shavings, crumbles, granules, fluff, regrind, parts, prills, and powders with numerous layouts using multiple inlets and outlets.

In addition to avoiding external contamination, food processors also increasingly expect conveyor systems to be designed for easy cleaning.  

In this regard, bucket elevators are particularly difficult to clean in preparation for production line changeovers.  To clean them, each bucket must be removed and cleaned inside and out to remove accumulated residue. 

Every minute spent disassembling a conveyor system for cleaning consumes valuable production time. Yet, if not cleaned properly, the food product being conveyed must be discarded due to contamination, which equates to lost profit. Or worse, consumers could be harmed, resulting in costly recalls, damage to brand and reputation, or even potential litigation and liability. 

With closed conveyors, cleaning is also a mixed bag.  Pneumatic conveyors are popular, enclosed systems, but cleaning can still be relatively time-consuming. Because high-pressure air is used to convey the product, it can create excessive breakage as materials get battered through a course of vertical and horizontal tubing, turns, and sweeps.

“When cleaning is factored in, closed-system tubular cable conveyor systems are actually less expensive to own and operate than pneumatic equipment,” says Judy.

In regard to maintaining cleanliness, tubular drag cable conveyor systems also offer more options for dry and wet tube conveyor cleaning.  These include brush boxes, urethane wipers, air knives, inline sponges, inline bristle brushes, and multi-step, essentially automated Clean-In-Place (CIP) wet cleaning.

“Compared to pneumatic conveyors, tubular cable conveyor systems also reduce product breakage and use less horsepower, which equates to less electrical use and less noise,” adds Judy.

Cleanliness is also a key consideration when selecting between cable and chain tubular drag conveyors, both of which come into contact with the food during operation.  Tubular chain conveyors have more surface area and connection points where residue can accumulate compared to a coated cable, which only has 20% of the surface area.

“Once a tubular cable conveyor system is installed, it dramatically reduces the cleaning and maintenance required,” says Judy.  He cites an example at a food processing facility when a tubular cable conveyor system by Cablevey was installed.  “What previously took about 14-man hours of cleaning [with a different, previous system] was accomplished in two hours,” he says.

Minimizing product breakage is another important advantage of enclosed tubular cable conveyors.  According to Judy, traditional conveyor systems can damage up to 10% of the product, but tubular cable conveyors dramatically reduce any such damage.  In one instance, a Canadian potato chip manufacturer was able to reduce breakage from 10% to less than 3%, a target goal that was guaranteed by the supplier of the tubular cable conveyor system.

Although there are many conveying options for food processing, few offer the same capability of preventing contamination and easing cleaning as closed system tubular cable conveyors, while also minimizing product degradation.  This combination of attributes, along with low energy requirements and design flexibility, make the conveyors worth investigating for food industry professionals looking for a competitive edge.

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Cablevey Conveyors is a global specialty conveyor manufacturer that designs, engineers, assembles and services tubular drag cable and disc conveyor systems. With customers in more than 65 countries, the company specializes in moving materials for food/beverage and industrial powder processors that seek food-grade conveying performance with systems ...

Cablevey Conveyors